Project Summary Interactive cancer communication systems (ICCS) have great potential to provide cancer patients with accurate information on their diseases and treatments in a cost-effective manner. While data suggest that ICCS may benefit cancer patients, important knowledge gaps remain: gaps that should be addressed before ICCS are more broadly incorporated into healthcare. Data are needed on ICCS effects on such outcomes as patients' emotional well being, on clinicians' reactions to clinical encounters, and on healthcare utilization and cost-effectiveness. In addition, almost all data on ICCS come from efficacy trials. Little is known about how much ICCS will be used, what their effects will be, and how to foster their use in real world healthcare contexts. This proposal describes a study that will be conducted within the Kaiser Permanente Northwest (KPNW) healthcare system. Breast cancer patients will be informed of the availability of a KPNW Breast Cancer Information website. The number of patients visiting that site will reflect interest in KPNW internet breast cancer resources and potential reach of an ICCS within the KPNW population. After entering the website, women (N=600) will be offered the opportunity to join a 2 X 2 randomized trial in which they can volunteer online to be randomized to either: (1.) a Basic ICCS that provides static information on KPNW resources and articles on breast cancer, or (2) an Enhanced ICCS condition that comprises those same static resources + CHESS (an ICCS that has benefited breast cancer patients in efficacy trials). CHESS availability will be crossed with a Prompt condition in which some women will have ICCS use prompted by letters and phone calls from KPNW while others will not. Outcome measures will include amount of ICCS use and women's ratings of cancer information competence, perceived social support, and emotional well being, Other outcomes will include healthcare utilization, cost-effectiveness, and clinician ratings of healthcare visits. The proposed research should provide information about the business and clinical cases for a comprehensive ICCS in the context of real world use for cancer care. This center grant focuses on CHESS, a computer program that is designed to give support and information to women with breast cancer. This Effectiveness study will show how CHESS works in real world healthcare setting, yielding new data on women's use of CHESS, whether CHESS helps women feel better informed and less anxious, and whether it reduces healthcare costs.